Method of drying berries especially thompson seedless raisins



Oct. 18 1927.

T. w. w. FoRREsT METHOD OF DRYING BERRIES ESPECIALLY THOMPSON SEEDLESS RAISINS Filed July 13, 1926 Wwf B www, 7L/.37,64

Patented oct. 1e, 1927.

UNITED lsrpxras 1,645,695 ,PATENT OFFICE THOMAs W. W.` FoRREsT, oF FRESNO, CALIFORIIIA, AssiGNoR 'ro 'suirsMAID vRAII'sIiN or CALIFORNIA.

GROWERs or CALIFORNIA, or FRESNO, CALIFORNIA, A COOPERATIVE ASSOCIATION METHOD or :DRYING BRRRIRS ESPECIALLY THoMrsoN siiEnLEssRAIsIits.

Application led July 13,

The invention relates to a method of drying berries forming a divisible part o f my copending application for patent iiled simultaneously herewith vunder Serial Number 6 122,083 covering the processing of dried berries, as the herein described and specially claimed portion of the process may have valuable application apart `from the process described in said application and other meth- 10 ods of vdrying may be substituted for it in said application. 5

The objects of the process are to provide a method of effectively heat drying berries, especially Thompson seedless raisins which have previously been treated to moisture, and

to carry this drying out at a relatively high n temperature yet Without scorching of the product. Agitating heating methods of drying raisins have been practiced heretofore, but the methods while successful with the larger raisins such as muscats have not operated properly on very small soft raisins such as the Thompson seedless or Sultanas as the very small bodies of these raisins and their extremely soft nature when moist, especially when hot and moist, makes them prone to agglutinate or melt and stick to hot metallic apparatus heretofore employed.

I have Overcome the difiiculty by the adoption of a new principle of agitation which comprises rolling the raisin berries rather than by slidablyagitating the berries while subjecting them to Contact with hot metal, and whereby a new portion of the berry 1s constantly presented to the heated metal as the same rolls along.

In the drawing hereto the showing is somewhat diagrammatic since a copendmg application simutaneously filed herewith under Serial Number 122,083 claims the apparatus and describes it more fully, whereas the present application relates to the process only and which may be carried out by other or modified apparatus.

The drawing represents in Figure 1 a ver- Lil) tical section through the apparatus, and in Figure 2 an enlarged cross section of the shaking grill.

In the appartus 5 is a suitable casing having an exhaust hood 5 topped by an exhaust pipe 16, to which a mildsuction is applied by any desired means.

Within the casing are any number of su- 1926. sei-iai No; 122,081.l

"centric or 'crank 2O from any desired vform of driving means not shown.

The shaker tables slantin reverse directioh as vindicated and are soarranged that berries Vdelivered to the lower endsl of the tablesl will crawl upward by'a rolling action for 1 charge over the highest ends of the :tables "so that the highest en'd OI" one table discharge to thev lowest end of the table below as indicated by the arrows from the source of delivery of the berries 1 through the supply chute 5.

This action of uphill rolling is caused by the angular relation of the suspension links 19 and amount ot' oscillation given the tables as well as being influenced by the speed of the same. f f

When several superimposed shaker tables are used the speed or throw or angularity of the links of each table successively is a trilie greater than the table next above, so that each table will have a capacity slightly in excess of the table discharging to it.

The tables are madeof longitudinal parallel metal bars in the form of a grill set so close that the berries to be treated will not 'y fall through, and provision is made for heating the grill by means of electric current from-the wires P so as to bring them to a temperature of approximately 750 F.

The lowermost grill discharges into a rotary gate 6 operated by any desired means not shown, so as to eject the treated product while preventing the ingress of air.

In actual construction the grill tables are f made Vof parallel bars or tubes and form in effect two grills one within the other, since every other kbar is secured to supporting means 21 suspended or supported on links 19 and shaken by rods 22 from the eccentric, while the other set of bars is similarly supported and hung on another set of links 19 and shakenby rods 22 from another oint in the eccentric or opposite throw o the crankso that a peculiar motion of the inter-- laced grills results in some of .the berries` l being rolled against the oppositely moving bars, and other berries getting a similar motion from those berries (see Fig. 2) all while advancing upward on the grill. The exact action of the bars and motion of the raisin berries is hard to deiine, but since raisins are not round bodies7 but Vhave iiattened sides and are sticky (especially when heat is Iapplied) it is thought that the eii'ect of the oppositely moving bars turns the raisins over due to slight adherence of the bodies to two oppositely moving surfaces, or some of the raisins to two oppositely moving raisins, tho since both grills are suspended on angularly arranged links the movement of the raisins as a whole is as stated upward and .with a rolling action.

In ,practice one only of the interlaced grills is heated as it mali-es for simpler elec trical construction, and the other of the pair of grills becomes hotby radiation from the heated one.

The grills may be of any capacity, length or number desired depending on the naturev and condition of the berries delivered to the apparatus, a simple passage of the same over the intensely heated grill under the rolling conditions mentioned will effect a perfect drying of the product in a few minutes and without any scorching, melting, or agglutinating of the mass.

I claim:

l. The method of heat drying raisins which comprises rolling` them along a heated metal grill. Y

2. The method of heat drying raisins which comprises rolling them along an upwardly slanted heated grill and discharging them from the upper end thereof.

3. The method of heat drying raisins which comprises rolling them along a metal grill heated to about 750 F.

4:. ln the processing of raisins, the ste-p of rolling the berries upward on an inclined grill for discharge from the upper end thereof.

5. The method ot drying berries which comprises rolling the berries between oppositely moving surfaces and at the same time in one general direction along said surfaces.

THOMAS W. W. FORREST. 

